Illustration of the noise cube for the GOODS-S field in ALMA Band 7 (see Sect. 3.2.1). Each cube consists of ten layers for different angular resolutions, as indicated in the bottom right of each layer. Each pixel represents a solid angle of 2 × 2 arcsec. The colour of each pixel indicates the lowest RMS noise available between all pointings covering this solid angle in that particular band and at this angular resolution. The enlarged cutout shows how, as a result, pointings with lower RMS overwrite those with higher RMS in cases of spatial overlap between pointings with similar angular resolution.